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Abstract:

An inductor pump system comprises a pump system, a ram system and a
bearing assembly. The pump system includes a platen configured to engage
a container. The ram system comprises a cylinder configured to support
the pump system, and a piston extendable from the cylinder to vary axial
positioning of the platen with respect to the container. The bearing
assembly links the piston to the cylinder and is configured to prevent
rotation of the pump system with respect to the ram system.

Claims:

1. An inductor pump system comprising: a pump system for dispensing a
fluid from a container; a base for receiving the container; and a fluid
activated ram for positioning the pump system axially with respect to the
base, the fluid activated ram comprising: a cylinder comprising: an upper
end; a lower end mounted to the base; and an interior; a piston
comprising: a first end disposed within the interior of the cylinder; and
a second end extending from the upper end of the cylinder and to which
the pump system is mounted; and a bearing assembly coupled to the
cylinder and engaging the piston to permit the piston to slide axially
from the cylinder and to prevent the piston from rotating within the
cylinder.

2. The inductor pump system of claim 1 wherein the piston comprises a
non-round cross-sectional profile.

3. The inductor pump system of claim 2 wherein the piston includes a flat
surface extending at least partially along a length of the piston between
the first end and the second end.

4. The inductor pump system of claim 2 wherein the bearing assembly
comprises: a bearing disposed between the cylinder and the piston, the
bearing including: an outer periphery that faces the cylinder; and an
inner periphery having a non-round profile to engage the cross-sectional
profile of the piston.

5. The inductor pump system of claim 4 and further comprising: a cylinder
end cap connected to the upper end of the cylinder, the cylinder end cap
comprising: an outer periphery having a profile to engage the interior of
the cylinder; and an inner periphery having a pocket to receive the outer
periphery of the bearing.

6. The inductor pump system of claim 5 and further comprising: a first
retaining ring coupled to the cylinder end cap to axially secure the
bearing to the pocket; and a first retaining pin connected to the
cylinder end cap and the bearing to prevent rotation of the bearing with
respect to the cylinder end cap.

7. The inductor pump system of claim 5 and further comprising: a seal
disposed between the cylinder end cap and the piston, the seal
comprising: an outer periphery engaging the cylinder end cap; an inner
periphery having a non-round profile to mate with the cross-sectional
profile of the piston; and a gland extending along the inner periphery
that forms an air seal against the piston.

8. The inductor pump system of claim 7 and further comprising: a rigid
seal retaining ring disposed radially outward of the seal to maintain the
gland in contact with the piston.

9. The inductor pump system of claim 5 and further comprising: a second
retaining ring coupled to the cylinder to axially secure the cylinder end
cap to the cylinder; a second retaining pin connected to the cylinder end
cap and the cylinder to prevent rotation of the cylinder end cap with
respect to the cylinder; and an O-ring seal disposed between the cylinder
and the cylinder end cap.

10. The inductor pump system of claim 1 wherein the pump system
comprises: a bracket connected to the second end of the piston to
overhang the base; a motor mounted to the bracket and having a drive
shaft; a pump coupled to the bracket and connected to the drive shaft;
and a platen connected to the pump.

11. The inductor pump system of claim 1 wherein the base comprises: a
platform coupled to the lower end of the cylinder to face the pump
system; and a pair of support brackets each extending between an edge of
the platform and the upper portion of the cylinder.

13. An end cap assembly for positioning a ram post within a hydraulic
cylinder, the end cap assembly comprising: an end cap ring body
comprising: an outer diameter having a profile to match that of an
interior of a hydraulic cylinder; and an inner diameter having: a bearing
pocket; and a seal groove; a bearing sleeve comprising: an outer
periphery that fits into the bearing pocket; and an inner periphery
having a non-round profile to mate with a ram post; and a ram post seal
comprising: an outer periphery that fits into the seal groove; and an
inner periphery having a non-round profile matching that of the bearing
sleeve.

14. The end cap assembly of claim 13 and further comprising: a first
retaining ring coupled to the end cap ring body to axially secure the
bearing sleeve to the bearing pocket; and a first retaining pin connected
to the end cap ring body and the bearing sleeve to prevent rotation of
the bearing sleeve with respect to the end cap ring body.

15. The end cap assembly of claim 14 wherein the ram post seal further
comprises: a gland extending along the inner periphery that forms an air
seal against the ram post.

16. The end cap assembly of claim 15 and further comprising: a rigid seal
retaining ring disposed radially outward of the ram post seal within the
seal groove to maintain the gland in contact with the ram post.

17. The end cap assembly of claim 14 and further comprising: a second
retaining ring positioned axially adjacent the end cap ring body; a
second retaining pin extending radially into the end cap ring body; and
an O-ring seal positioned radially outward of the end cap ring body.

18. An inductor pump system comprising: a pump system including a platen
configured to engage a container; a ram system comprising: a cylinder
configured to support the pump system; and a piston extendable from the
cylinder to vary axial positioning of the platen with respect to the
container; and a bearing assembly linking the piston to the cylinder and
configured to prevent rotation of the pump system with respect to the ram
system.

19. The inductor pump system of claim 18 wherein: the piston comprises a
non-round cross-sectional profile; and the bearing assembly further
comprises: an end cap that engages the cylinder; and a bearing sleeve
connected to the end cap and having an inner diameter through which the
piston extends, the inner diameter mating with the non-round
cross-sectional profile of the piston to prevent rotation of the piston
within the cylinder.

20. The inductor pump system of claim 19 wherein the bearing assembly
further comprises: a seal that mates around an entire periphery of the
non-round cross-sectional profile.

Description:

CROSS-REFERENCE TO RELATED APPLICATION(S)

[0001] This application claims priority under 35 U.S.C. §120 to U.S.
provisional application Ser. No. 61/294,322, entitled "NON-ROTATING
SINGLE POST RAM," filed Jan. 12, 2010 by inventor Paul R. Quam, the
contents of which are incorporated by this reference.

BACKGROUND

[0002] The present invention relates generally to inductor pumps for
pumping highly viscous fluid from containers. In particular, the present
invention relates to ram posts that extend from linear actuators for
lifting and lowering platens used to push the fluid from the container.

[0003] Inductor pumps typically comprise a linear pneumatic ram that
forces a pipe having a platen into a drum. The platen includes a central
bore that leads to a passageway in the pipe. As the platen is lowered
into the drum by the pneumatic ram, the highly viscous fluid is forced
into the central bore and up the passageway. The fluid is pushed into a
pneumatically operated pump that forces pressurized fluid through a hose
and into a dispensing device where an operator can dispense a metered
amount of fluid into some other typically smaller container.

[0004] Typical pneumatic rams comprise a piston that is configured to
extend from a cylinder when pneumatic pressure is applied between ends of
the cylinder and piston. The piston and cylinder are typically round in
cross-section, thus allowing the piston to rotate within the cylinder.
Operators of inductor pump systems must carefully align the container
with the platen to avoid binding. Large inductor pump systems include a
pair of rams that straddle the platen and container. The platen is thus
immobile with respect to lateral movement between the platen and
container. An operator need only ensure that the container is aligned
with the platen. In smaller inductor pump systems, only a single ram is
used such that the platen is capable of rotating with respect to the
container. Thus, an operator must maintain both the platen and the
container in alignment. Additional brackets and guides must be externally
mounted to the pump system to immobilize lateral movement of the platen.
There is, therefore, a need for an inductor pump system that more readily
aligns the platen with a container.

SUMMARY

[0005] The present invention is directed to inductor pump systems and
bearing assemblies for ram posts used in inductor pump systems.

[0006] In one embodiment of the invention, an inductor pump system
comprises a pump system, a ram system and a bearing assembly. The pump
system includes a platen configured to engage a container. The ram system
comprises a cylinder configured to support the pump system, and a piston
extendable from the cylinder to vary axial positioning of the platen with
respect to the container. The bearing assembly links the piston to the
cylinder and is configured to prevent rotation of the pump system with
respect to the ram system.

[0007] In another embodiment of the invention, an end cap assembly
comprises a ring body, a bearing sleeve and a ram post seal. The end cap
ring body comprises an outer diameter having a profile to match that of
an interior of a hydraulic cylinder, and an inner diameter having a
bearing pocket and a seal groove. The bearing sleeve comprises an outer
periphery that fits into the bearing pocket, and an inner periphery
having a non-round profile to mate with a ram post. The ram post seal
comprises an outer periphery that fits into the seal groove, and an inner
periphery having a non-round profile matching that of the bearing sleeve.

BRIEF DESCRIPTION OF THE DRAWINGS

[0008] FIG. 1 is a perspective view of an inductor pump system having a
non-rotating ram post of the present invention disposed within a ram
cylinder.

[0009] FIG. 2 is a side view of the inductor pump system of FIG. 1 in
which the ram post (partially in section) is extended from the ram
cylinder.

[0010] FIG. 3 is a perspective view of the ram post of FIG. 1 with a
quarter section removed from the cylinder to show connection of a bearing
assembly.

[0011] FIG. 4 is an exploded view of the bearing assembly of FIG. 3
showing a bearing surface on the ram post, a bearing and a seal.

[0013] Piston 32 is fully seated within cylinder 30 of ram 12, as shown in
FIG. 1, and extends to lift platen assembly 16 from container 24, as
shown in FIG. 2. Piston 32 is also referred to as a ram post. Platform 26
of base 14 is connected to a lower end of cylinder 30 and extends
underneath platen assembly 16 to receive container 24. Supports 28A and
28B extend from side edges of platform 26 on either side of container 24
up to an upper portion of cylinder 30. Base 14 thus provides a footprint
wide enough to prevent tipping of inductor pump system 10. Support
bracket 36 is mounted to a top, exposed end of piston 32. Air motor 18 is
mounted to the top of support bracket 36. Pump 20 is suspended from the
bottom of support bracket 36 by pins 46 that connect to housing 40. Drive
shaft 48 extends from air motor 18 to connect with pump 20. Pump 20 is
connected to ram pipe 22 at inlet 42 and to a dispensing device (not
shown) through a hose at outlet 44. Hub 50 of platen assembly 16 connects
to ram pipe 22.

[0014] In operation, pressurized air from a separate air source (not
shown) is provided to air controls to operate ram 12 and air motor 18. An
inlet of air motor 18 and cylinder 30 of ram 12 receive pressurized air
from the air controls. Ram 12 is used to lift support bracket 36 up and
away from platform 26 such that an empty container can be removed from
platform 26 and a full container can be positioned between platform 26
and platen assembly 16. Specifically, the air controls are operated so
that pressurized air is delivered to ram 12 and allowed to enter cylinder
30. The pressurized air travels to the bottom of cylinder 30 and pushes
piston 32 up and out of cylinder 30, pushing support bracket 36 away from
platform 26 and lifting platen assembly 16 out of container 24. Bearing
assembly 34 prevents air from leaking out of cylinder 30.

[0015] Container 24, which is filled with a fluid or viscous material that
is to be dispensed by system 10, is disposed on platform 26 so that
container 24 is accessible to platen assembly 16. As will be discussed in
greater detail with reference to FIG. 3, bearing assembly 34 engages
piston 32 to prevent bracket 36 from moving laterally with respect to
platform 26. As such, alignment of platen assembly 16 with container 24
is more easily accomplished by an operator.

[0016] An operator adjusts the air controls to provide pressurized air to
the top of cylinder 30 to push piston 32 downward, allowing platen
assembly 16 to fall into container 24. Platen assembly 16 enters
container 24, and the weight of platen assembly 16 and the air pressure
against piston 32 pushes material into a central bore located in hub 50
such that the material travels into ram pipe 22 and up to pump 20. An
operator adjusts the air controls to permit pressurized air to flow to
air motor 18, which causes air motor 18 to actuate drive shaft 48.
Depending on the type of pump used, drive shaft 48 rotates or
reciprocates to drive pump 20. Pump 20 pressurizes the material provided
by ram pipe 22 and distributes the pressurized material to outlet 44. A
dispensing device connected to pump 20 at outlet 44 is used to meter
material pressurized by system 10.

[0017] As material from container 24 is consumed, platen assembly 16 falls
to the bottom of container 24. Wiper ring 52 of platen assembly 16
engages the side of container 24 to push the viscous material downward
and into pipe 22. As platen assembly 16 descends into container 24, wiper
ring 52 deflects to engage the sidewalls of container 24 to seal and
scrape against container 24. Bleed stick 54 can be manually actuated to
allow airflow into and out of container 24 through a vent in hub 50. To
remove platen assembly 16 from container 24, an operator again adjusts
the air controls to provide pressurized air to cylinder 30 and uses bleed
stick 54 to permit air to enter container 24.

[0018] As mentioned above, bearing assembly 34 of the present invention
prevents platen assembly from moving laterally with respect to platform
26. Specifically, bearing surface 38 of piston 32 engages with a mating
bearing surface in bearing assembly 34 to prevent piston 32 from rotating
within cylinder 30. This also prevents bracket 36 from rotating about
cylinder 30 such that an operator need only align platen assembly 16 with
container 24 once. Continuously holding bracket 36 in place while platen
assembly 16 descends into container 24 is not needed. Furthermore, with
platen assembly 16 withdrawn from container 24, bracket 36 will not
rotate air motor 18, pump 20 and platen assembly 16 laterally away from
platform 26 such that the center of gravity of pump system 10 does not
change. Thus, the footprint of platform 26 and brackets 28A and 28B can
be reduced without the need to accommodate a range of lateral positions
of the pump components of system 10.

[0020] An upper end of piston 32 extends from interior 74 of cylinder 30
at upper end 76. Bearing assembly 34 maintains piston 32 properly aligned
within cylinder 30, prevents piston 32 from rotating within cylinder 30
and prevents air from escaping cylinder 30. End cap 58 is positioned
within interior 74 at upper end 76. In various embodiments, end cap 58 is
comprised of metal, such as a carbon steel or stainless steel, or
plastic, such as a nylon or polytetrafluoroethylene (PTFE). End cap 58
comprises a sleeve having an outer periphery and an inner periphery. In
one embodiment, end cap 58 comprises an annulus having a radial outer
diameter and a radial inner diameter. The outer periphery of end cap 58
faces towards cylinder 30 and the inner periphery of end cap 58 faces
towards piston 32.

[0021] The outer periphery of end cap 58 couples to cylinder 30 using
second retaining ring 68 and second retaining pin 70. Retaining pin 70
extends through a hole in cylinder 30 and into a mating bore in end cap
58. In the described embodiment, retaining pin 70 comprises a metal
spring pin that is compressed within the hole of cylinder 30 and bore of
end cap 58. Retaining pin 70 prevents rotation of end cap 58 relative to
interior 74 of cylinder 30. Retaining pin 70 is one of three retaining
pins spaced equally around the circumference of cylinder 30. Retaining
ring 68 prevents outward axial displacement of end cap 58. Retaining ring
68 comprises a split ring that flexes to fit into groove 77. Ring 68
extends partially into groove 77 of cylinder 30 and partially overhangs
an upper end surface of end cap 58. Outer seal groove 82 engages cylinder
30 to trap and compress cap seal 72, which inhibits air from leaking out
of cylinder 30. In the disclosed embodiment, cap seal 72 comprises a
rubber O-ring seal.

[0022] The inner periphery of end cap 58 couples with bearing 56 and
piston seal 60. Bearing 56 is secured to the inner periphery of end cap
58 using first retaining ring 64 and first retaining pin 66.
Specifically, bearing 56 is positioned against shoulder 84 of pocket 78.
Retaining pin 66 extends through a hole in end cap 58 and into mating
detent 87 in bearing 56. In the described embodiment, retaining pin 66
comprises a metal spring pin that is compressed within the hole of end
cap 58 and bore of bearing 56. Retaining pin 66 prevents rotation of
bearing 56 relative to end cap 58. Retaining pin 66 is one of three
retaining pins spaced equally around the circumference of bearing 56.
Retaining ring 64 prevents axial displacement of bearing 56. Retaining
ring 64 comprises a split ring that flexes to fit into groove 86. Ring 64
extends partially into groove 86 of end cap 58 and partially overhangs an
inner end surface of bearing 56. Inner seal groove 80 is disposed on the
inner periphery of end cap 58 to face piston 32 and is configured to
retain piston seal 60 and ring 62. Piston seal 60 comprises a flexible
and resilient material that can be deformed to fit within groove 80. Ring
62 comprises a split ring that flexes to fit into groove 80. Ring 62
extends partially into groove 80 and partially overhangs piston seal 60.

[0023] Mounted as such, seal 60 and bearing 56 engage piston 32 when
piston 32 is inserted into end cap 58. Specifically, bearing 56 includes
mating geometric features that mount flush with bearing surface 38 of
piston 32 to prevent rotation of piston 32. Bearing 56 comprises a rigid
material that has a low coefficient of friction. As such, bearing surface
38 of piston 32 is inhibited from rotating and deforming bearing 56, but
bearing surface 38 can slide along bearing 56 to allow piston 32 to
extend from cylinder 30. In one embodiment, bearing 56 is comprised of
plastic, such as a nylon or PTFE.

[0024] Piston seal 60 includes mating geometric features that mount flush
with bearing surface 38 of piston 32 to prevent air from escaping
interior 74 at piston 32. Piston seal 60 tightly engages the entire
periphery of piston 32. In one embodiment, piston seal 60 is comprised of
rubber. Ring 62 comprises a disk-like body that is positioned axially
outward of piston seal 60 to cover and protect seal 60. Ring 62 also
assists in keeping piston seal 60 engaged with piston 32. In one
embodiment, ring 62 is comprised of metal, such as a carbon steel or
stainless steel.

[0026] Piston 32 comprises an elongate ram post that has a non-round
cross-sectional profile. In the embodiment shown, piston 32 has a
D-shaped cross-sectional profile. In other embodiments, piston 32 can
have other non-round cross-sectional profiles, such as square or oval.
Typically, piston 32 comprises a round post that is machined to include
bearing surface 38. Bearing surface 38 comprises a flat portion that
engages bearing 56 to prevent relative rotation. In other embodiments,
piston 32 can be cast or otherwise manufactured with an inherent
non-rotation feature such as bearing surface 38.

[0027] Piston 32 includes upper end 100 for coupling with bracket 36 (FIG.
1). Upper end 100 includes post 102 around which a bore in bracket 36 is
positioned. A pin can be inserted through a hole in bracket 36 and into
bore 104 to prevent bracket 36 from rotating on piston 32. Alternatively,
post 102 can be square of have another shape to prevent rotation of
bracket 36. Bearing 56 is assembled with end cap 58 and cylinder 30 (FIG.
3) such that bracket 36 extends over platform 26 (FIG. 2) when flat 92 of
bearing 56 aligns with bearing surface 38 of piston 32. For convenience,
hole 104 is typically placed perpendicular to bearing surface 38.

[0028] Outer periphery 90 of bearing 56 is coupled to end cap 58 such as
by positioning retaining pin 66 in detent 87. Inner periphery 88 of
bearing 56 is fitted around piston 32 and has a profile that mates with
the cross-sectional profile of piston 32. Bearing 56 fits snuggly around
piston 32 to reduce play or leeway between inner periphery 88 and piston
32 without disadvantageously interfering with axial movement of piston
32. Specifically, inner periphery 88 is sized to push flat 92 firmly
flush against bearing surface 38 to prevent rotation of piston 32. Inner
periphery 88 is also sized to provide a level of air sealing between
piston 32 and bearing 56 in addition to that provided by piston seal 60.

[0029] Outer periphery 96 of seal 60 is positioned within groove 80 to
engage end cap 58 while inner periphery 94 engages piston 32. Inner
periphery 94 has a profile that mates with the cross-sectional profile of
piston 32. Seal 60 fits snuggly around piston 32 to reduce or eliminate
the ability of air to flow between piston 32 and seal 60. For example,
seal 60 produces an interference fit with piston 32. Specifically, flat
98 of seal 60 engages flush with bearing surface 38. Corners of seal 60
between flat 98 and the arcuate portion of inner periphery 94 are
provided with additional material such that adequate sealing is provided
at the corners of bearing surface 38. Inner periphery 94 includes gland
99 to engage piston 32. Gland 99 includes an arcuate surface that faces
piston 32 to trap a volume of air between piston 32 and seal 60. The
arcuate surface includes a flange that deflects to tightly seat against
piston 32 to prevent air from within cylinder 30 from penetrating into
gland 99. The flange can deflect when piston 32 moves and changes
direction within cylinder 30 while other portions of seal 60 remain
engaged with piston 32.

[0030] The present invention provides an end cap assembly for an inductor
pump system that prevents a ram post from rotating within a hydraulic
cylinder. The end cap includes a flexible, non-round seal that mates with
a non-round ram post to prevent air from escaping the cylinder. The end
cap also includes a rigid, non-round bearing that mates with the
non-round ram post to prevent the ram post from spinning within end cap
assembly. The end cap assembly is itself mounted to the cylinder in a
non-rotatable manner to prevent the end cap from spinning within the
cylinder. As such a pump system comprising an air motor, pump, and platen
mounted to the cylinder will not rotate with respect to a base of the
cylinder where a platform and container of material for the pump system
are positioned. Immobilizing movement of the pump system with respect to
the container facilitates alignment of the container with the platen,
thereby facilitating expedient operation of the inductor pump system.
Additionally, the size of the platform that supports the cylinder can be
kept small, as the weight of the pump system cannot be moved laterally to
reposition the center of gravity of the inductor pump system.
Furthermore, the end cap assembly can be used with conventional cylinders
and ram posts, such as by machining cylindrical ram posts. The end cap
assembly is self-contained within the cylinder such that external
brackets and guides to immobilize the pump system are not needed.

[0031] While the invention has been described with reference to an
exemplary embodiment(s), it will be understood by those skilled in the
art that various changes may be made and equivalents may be substituted
for elements thereof without departing from the scope of the invention.
In addition, many modifications may be made to adapt a particular
situation or material to the teachings of the invention without departing
from the essential scope thereof. Therefore, it is intended that the
invention not be limited to the particular embodiment(s) disclosed, but
that the invention will include all embodiments falling within the scope
of the appended claims.

Patent applications by Paul R. Quam, Minneapolis, MN US

Patent applications by Graco Minnesota, Inc.

Patent applications in all subclasses Liquid pumped by supplying or exhausting gaseous motive fluid to or from pumping chamber